{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{6}{c}}
\hline\hline
          &\multicolumn{1}{c}{(1)}         &\multicolumn{1}{c}{(2)}         &\multicolumn{1}{c}{(3)}         &\multicolumn{1}{c}{(4)}         &\multicolumn{1}{c}{(5)}         &\multicolumn{1}{c}{(6)}         \\
\hline
ST        &   -0.083         &   -0.132         &   -0.111\sym{*}  &   -0.253\sym{**} &    0.036         &    0.020         \\
          &  (0.052)         &  (0.082)         &  (0.058)         &  (0.111)         &  (0.111)         &  (0.127)         \\
\hline
\(N\)     &    24586         &    27749         &    16531         &    14142         &     8228         &     8903         \\
\(R^{2}\) &    0.043         &    0.044         &    0.045         &    0.047         &    0.046         &    0.054         \\
\hline\hline
\end{tabular}
}
